Java spring post form one to many relationship - spring-mvc

Question

I'm trying to get POST form data on controller of the object have one to many relationship. Like below code
My Notification Model
private long id;
#NotBlank(message = ERROR.NOT_EMPTY)
private String title;
#NotBlank(message = ERROR.NOT_EMPTY)
private String content;
// One Notification has many User
private List<NotificationUser> listNotificationUser;;
// Getter and setter method
My controller
#RequestMapping(value = "notification/add", method = RequestMethod.GET)
public String create(ModelMap model) {
ArrayList<User> listUser = userService.getAllUsername();
model.put("user", listUser);
model.addAttribute("notification", new Notification());
return "notification/add";
}
#RequestMapping(value = "notification/add", method = RequestMethod.POST)
public String create(ModelMap model, HttpServletRequest request,
#Valid #ModelAttribute(value = "notification") Notification notification, BindingResult bindingResult) {
....
}
My .jsp
<form:form method="POST" action="add" name="addForm" commandName="notification">
<!-- Other input -->
<form:select path="listNotificationUser" multiple="multiple" id="name" name="itemValue">
<form:options />
<form:options items="${user}" itemValue="id" itemLabel="name" />
</form:select>
<!-- Other input -->
</form:form>
When I submit POST form to controller, the field notification.listNotificationUser always is null (other field is fine).
I was search and try some solution but it not working.

Answer 1

I guess your problem its you have a typo in your form:select. You are defining 2 options blocks, and I guess you want to define just an empty option. So should be like this
<form:select path="listNotificationUser" multiple="multiple" id="name" name="itemValue">
<!-- Some value you can identify as empty option-->
<form:option value="0" label="--Options--"/>
<form:options items="${user}" itemValue="id" itemLabel="name" />
</form:select>